Sex-mismatch influence on survival after heart transplantation: A systematic review and meta-analysis of observational studies

Outcomes of Heart Transplant Using High Donor Sequence Number Offers

INTRODUCTION

Higher donor sequence numbers (DSNs) might spark provider concern about poor donor quality. We evaluated characteristics of high-DSN offers used for transplant and compared outcomes of high- and low-DSN transplants.

MATERIALS AND METHODS

Adult isolated heart transplants between January 1, 2015, and December 31, 2022, were identified from the organ procurement and transplantation network database and stratified into high (≥42) and low (<42) DSN. Postoperative outcomes, including predischarge complications, hospital length of stay, and survival at 1 and 3 y, were evaluated using multivariable regressions.

RESULTS

A total of 21,217 recipients met the inclusion criteria, with 2131 (10.0%) classified as high-DSN. Donor factors associated with greater odds of high-DSN at acceptance included older age, higher creatinine, diabetes, hypertension, and lower left ventricular ejection fraction. Recipients accepting high-DSN offers were older and more likely to be female, of blood type O, and have lower status at transplant. High- and low-DSN transplants had similar likelihood of stroke (3.2% versus 3.5%; P = 0.97), dialysis (12.3% versus 13.5%; P = 0.12), pacemaker implant (2.3% versus 2.1%; P = 0.64), had similar lengths of stay (16 [12-24] versus 16 [12-25] days, P = 0.38), and survival at 1 (91.6% versus 91.6%; aHR 0.85 [0.72-1.02], P = 0.08) and 3 y (84.2% versus 85.1%; aHR 0.91 [0.79-1.05], P = 0.21) post-transplant.

CONCLUSIONS

High-DSN (≥42) was not an independent risk factor for post-transplant mortality and should not be the sole deterrent to acceptance. Accepting high-DSN organs may increase access to transplantation for lower-status candidates.

Recipient donor sex combinations in solid organ transplantation and impact on clinical outcome: A scoping review

INTRODUCTION

Solid organ transplantation (SOT) is a lifesaving treatment for end-stage organ failure. Although many factors affect the success of organ transplantation, recipient and donor sex are important biological factors influencing transplant outcome. However, the impact of the four possible recipient and donor sex combinations (RDSC) on transplant outcome remains largely unclear.

METHODS

A scoping review was carried out focusing on studies examining the association between RDSC and outcomes (mortality, graft rejection, and infection) after heart, lung, liver, and kidney transplantation. All studies up to February 2023 were included.

RESULTS

Multiple studies published between 1998 and 2022 show that RDSC is an important factor affecting the outcome after organ transplantation. Male recipients of SOT have a higher risk of mortality and graft failure than female recipients. Differences regarding the causes of death are observed. Female recipients on the other hand are more susceptible to infections after SOT.

CONCLUSION

Differences in underlying illnesses as well as age, immunosuppressive therapy and underlying biological mechanisms among male and female SOT recipients affect the post-transplant outcome. However, the precise mechanisms influencing the interaction between RDSC and post-transplant outcome remain largely unclear. A better understanding of how to identify and modulate these factors may improve outcome, which is particularly important in light of the worldwide organ shortage. An analysis for differences of etiology and causes of graft loss or mortality, respectively, is warranted across the RDSC groups.

PRACTITIONER POINTS

Recipient and donor sex combinations affect outcome after solid organ transplantation. While female recipients are more susceptible to infections after solid organ transplantation, they have higher overall survival following SOT, with causes of death differing from male recipients. Sex-differences should be taken into account in the post-transplant management.

Effect of renal function under left ventricular assist device support on the cardiac function and clinical events after heart transplantation

AIM

We investigated the effects of pre-transplantation renal dysfunction under left ventricular assisted device (LVAD) support on post-transplantation cardiac function, and patient prognosis after heart transplantation (HTx).

METHOD

All patients who were bridged by LVAD and underwent HTx at our hospital between 2007 and 2022 were included in this study. Patients were classified into two groups based on estimated glomerular filtration rate (eGFR) before HTx: renal dysfunction (RD) group (eGFR < 60 mL/min/1.73 m2 ) and non-renal dysfunction (NRD) group.

RESULT

A total of 132 patients were analyzed, of whom 48 were classified into the RD group and 84 into the NRD group (RD group, 47.9 ± 10.1 years; NRD group, 38.4 ± 11.9 years, p < .0001). Under LVAD support before HTx, the RD group tended to have a history of right ventricular failure (RD group, nine (19%); NRD group, seven (8%); p = .098). After HTx, the echocardiographic parameters did not differ between the two groups in the long term. Furthermore, more concise hemodynamic parameters, exemplified by right heart catheterization, were not significantly different between the two groups. Regarding graft rejection, no significant differences were found in acute cellular rejection and cardiac allograft vasculopathy following HTx. In contrast, patients with RD before HTx had significantly increased mortality in the chronic phase after HTx and initiation of maintenance dialysis, without any overt changes in cardiac function.

CONCLUSION

Pre-transplantation renal dysfunction under LVAD support significantly affected clinical course after HTx without any overt changes in graft cardiac function.

Addressing Barriers for Women with Advanced Heart Failure

PURPOSE OF REVIEW

Describe disparities in diagnosis and management between men and women with advanced heart failure (HF). Our goal is to identify barriers and suggest solutions.

RECENT FINDINGS

Women with advanced HF are less likely to undergo diagnostic testing and procedures (i.e., revascularization, implantable cardioverter defibrillators, cardiac resynchronization therapy, mechanical circulatory support, and orthotopic heart transplantation). Disparities related to gender create less favorable outcomes for women with advanced HF. The issues arise from access to care, paucity of knowledge, enrollment in clinical trials, and eligibility for advanced therapies. In this review, we propose a call to action to level the playing field in order to improve survival in women with advanced HF.

Sex differences in clinical characteristics and outcomes in patients undergoing heart transplantation

AIMS

Whether sex affects selection for and outcomes after heart transplantation (HTx) remains unclear. We aimed to show sex differences in pre-transplant characteristics and outcomes after HTx.

METHODS AND RESULTS

From 1995 to 2019, 49 200 HTx recipients were prospectively enrolled in the Organ Procurement and Transplantation Network. Logistic regression models were used to evaluate clinical characteristics by sex. Multivariable Cox regression models were fitted to assess sex differences in all-cause mortality, cardiovascular mortality, graft failure, cardiac allograft vasculopathy (CAV), and malignancy. In 49 200 patients (median age 55 years, interquartile range 46-62; 24.6% women), 49 732 events occurred during a median follow-up of 8.1 years. Men were older than women, had more often ischaemic cardiomyopathy (odds ratio [OR] 3.26, 95% confidence interval [CI] 3.11-3.42; P < 0.001), and a higher burden of cardiovascular risk factors, whereas women had less malignancies (OR 0.47, CI 0.44-0.51; P < 0.001). Men were more often treated in intensive care unit (OR 1.24, CI 1.12-1.37; P < 0.001) with a higher need for ventilatory (OR 1.24, CI 1.17-1.32; P < 0.001) or VAD (OR 1.53, CI 1.45-1.63; P < 0.001) support. After multivariable adjustment, men had a higher risk for CAV (hazard ratio [HR] 1.21, CI 1.13-1.29; P < 0.001) and malignancy (HR 1.80, CI 1.62-2.00; P < 0.001). There were no differences in all-cause mortality, cardiovascular mortality, and graft failure between sexes.

CONCLUSIONS

In this US transplant registry, men and women differed in pre-transplant characteristics. Male sex was independently associated with incident CAV and malignancy even after multivariable adjustment. Our results underline the need for better personalized post-HTx management and care.

The effect of sex inequality on solid organ transplantation: A systematic review and meta-analysis

BACKGROUND

Sex disparities are related to biological differences, which may have significant impact on patient and allograft outcomes. The aim was to investigate the impact of sex on clinical and safety outcomes after solid organ transplantation (SOT).

METHODS

A systematic review and meta-analysis was performed. Observational studies comparing females vs. males after SOT were considered for inclusion after a systematic search of the Pubmed, Cochrane Library, and Web of Science databases conducted from 2016 to 2021. Primary outcome was mortality. PROSPERO register number: CRD42021282615.

RESULTS

After retrieving 1103 studies, 22 observational studies (1,045,380 subjects) were finally deemed eligible for inclusion. Females accounted 36.3% of SOT recipients, but presented significantly lower mortality (odds ratio (OR): 0.87, 95% confidence interval (CI): 0.83-0.92, I2=78%). In subgroup analyses, mortality was significantly lower in females undergoing liver (OR: 0.89 95%CI: 0.86-0.92, I2=0%) or kidney transplantation (OR: 0.82 95%CI: 0.76-0.89, I2=72%). Male sex was consistently reported as a protective factor against hospital readmission. Among the outcomes, allograft dysfunction was influenced by a combination of donor-recipient sex and age. Data on overall infections were inconclusive. Several reports suggest a higher risk of malignancy among males.

CONCLUSIONS

Females represent one-third of SOT recipients but have higher survival rates than males after liver and kidney transplantation. The impact on graft dysfunction was heterogeneous. While further research is warranted, our findings should encourage clinicians and researchers to consider sex as a factor when taking decisions regarding SOT management.

Sex differences in patients undergoing heart transplantation and LVAD therapy

INTRODUCTION

Left ventricular assist device (LVAD) and heart transplantation (HT) are the two life-sustaining therapies that have revolutionized the management of end-stage heart failure (HF). Yet, significant sex differences exist with respect to their use and effects.

AREAS COVERED

This review summarizes sex differences in the utilization, outcomes, and complications of LVAD and HT. Particular emphasis is placed on leading clinical trials in the field, historical and recent large registries-based analyses, as well as contemporary technological and policy changes affecting these differences.

EXPERT OPINION

Women with advanced HF remain under-treated with guideline-directed medical therapy and are less likely to be referred for consideration for LVAD and HT. This remains true despite newer LVAD technology and the new heart transplant allocation system. Community outreach, education, as well as increased representation of women in clinical research may reduce inequities.

Residual Pulmonary Vascular Resistance Increase Under Left Ventricular Assist Device Support Predicts Long-Term Cardiac Function After Heart Transplantation

Aims

We compared hemodynamics and clinical events after heart transplantation (HTx) in patients stratified by the severity of residual pulmonary vascular resistance (PVR) after left ventricular assist device (LVAD) implantation for bridge to transplantation.

Methods

We retrospectively analyzed patients who had undergone HTx at the University of Tokyo Hospital. We defined the high PVR group as patients with PVR of >3 Wood Units (WU) as measured by right heart catheterization performed 1 month after LVAD implantation.

Results

We included 85 consecutive HTx recipients, 20 of whom were classified in the high PVR group and 65 in the low PVR group. The difference in PVR between the two groups became apparent at 2 years after HTx (the high PVR group: 1.77 ± 0.41 WU, the low PVR group: 1.24 ± 0.59 WU, p = 0.0009). The differences in mean pulmonary artery pressure (mPAP), mean right arterial pressure (mRAP), and mean pulmonary capillary wedge pressure (mPCWP) tended to increase from the first year after HTx, and were all significantly higher in the high PVR group at 3 years after HTx (mPAP: 22.7 ± 9.0 mm Hg vs. 15.4 ± 4.3 mm Hg, p = 0.0009, mRAP: 7.2 ± 3.6 mm Hg vs. 4.1 ± 2.1 mm Hg, p = 0.0042, and mPCWP: 13.4 ± 4.5 mm Hg, 8.8 ± 3.3 mm Hg, p = 0.0040). In addition, pulmonary artery pulsatility index was significantly lower in the high PVR group than in the low PVR group at 3 years after HTx (2.51 ± 1.00 vs. 5.21 ± 3.23, p = 0.0033). The composite event including hospitalization for heart failure, diuretic use, and elevated intracardiac pressure (mRAP ≥ 12 mm Hg or mPCWP ≥ 18 mm Hg) between the two groups was significantly more common in the high PVR group. Residual high PVR was still an important predictor (hazard ratio 6.5, 95% confidence interval 2.0–21.6, and p = 0.0023) after multivariate Cox regression analysis.

Conclusion

Our study demonstrates that patients with residual high PVR under LVAD implantation showed the increase of right and left atrial pressure in the chronic phase after HTx.

The outcomes of marginal donor hearts compared with ideal donors: a single-center experience in Iran

Background

Heart transplantation has been considered the gold-standard treatment for patients with end-stage heart failure. This study assessed the survival outcomes of marginal donor hearts compared with ideal donor hearts in Iran.

Methods

This retrospective study is based on the follow-up data of heart donors and recipients in the Sina Hospital Organ Procurement Unit. Among the 93 participants, 75 were categorized as ideal donors (group A) and 18 as marginal donors (group B). Group C included heart recipients who received a standard organ, and group D included heart recipients who received a marginal one. To analyze differences in patient characteristics among the groups, posttransplant heart survival was assessed in all groups. All data were obtained from the hospital records.

Results

The mean age of the donors was 26.27±11.44 years (median age, 28 years). The marginal age showed a significant association with donor age. The age of recipients had a significant effect on survival days in the ideal group. Most patients survived for at least 1 year, with a median of 645 days in recipients from marginal donors and 689 days in recipients from ideal donors.

Conclusions

Considering the lack of organ availability in Iran, it may be possible to use marginal donors for marginal recipients, therefore reducing the number of people on the waitlist. We also recommend establishing a national marginal donor system specifically for Iranian patients to extend the donor pool.

Impact of various sizing metrics on female donor to male recipient heart transplant outcomes

BACKGROUND

This study evaluated the impact of various sizing metrics on outcomes of female donor to male recipient orthotopic heart transplantation (OHT).

METHODS

We queried the United Network of Organ Sharing database to analyze all isolated, primary adult OHTs from January 1, 2010 to January 20, 020. Patients were stratified by donor-recipient sex pairing. Logistic regression was used to investigate risk-adjusted effects of current size matching criteria (weight ratio, body mass index [BMI] ratio, predicted heart mass [pHM] ratio) on 1-year posttransplant mortality. Kaplan-Meier analysis was used to compare posttransplant survival among cohorts.

RESULTS

A total of 22,450 patients were analyzed, of which 3019 (13.4%) underwent female-to-male transplantation. Of sex-matched pairs, female-to-male donation had the lowest proportion of undersized hearts using weight and BMI ratio metrics (10.5% and 5.2%) but had the highest proportion of undersizing using pHM metrics (48.1%) (all p < 0.001). Female-to-male recipients had the lowest rate of unadjusted 1-year survival (90.0%, p = 0.0169), and increased hazards of mortality after risk adjustment (odds ratio [OR]: 1.17, 95% confidence interval [CI]: 1.01-1.36, p = 0.034). Undersizing using pHM (donor-recipient ratio <0.85) was the only metric found to be associated in increased mortality after risk adjustment (OR: 1.32, 95% CI: 1.02-1.71, p = 0.035).

CONCLUSION

Female-to-male heart transplantation has the worst survival of all sex-matching combinations. Although female donors in this cohort are appropriately sized using traditional metrics, half are under-sized using pHM. This, combined with its strong association with mortality, underscores the importance of routine pHM assessment when evaluating female donors for male recipients.

Influence of Sex-Mismatch on Prognosis After Heart Transplantation

The influence of donor and recipient sex on prognosis after heart transplantation has been analyzed in single, multi-center studies, and international registries. In most of them, sex-mismatch was identified as a risk factor for the worst prognosis, especially in men recipients of female heart. This could be attributed to physiological differences between women and men, differences in complications rates after heart transplantation (rejection, cardiovascular allograft vasculopathy, and primary graft failure), and pulmonary hypertension of the recipient. Confounding variables as age, urgent transplantation, and size-mismatch should also be considered. When allocating a graft, sex-mismatch should be considered but its influence in long-term survival should be further explored.

Sex Influence on Heart Failure Prognosis

Heart failure (HF) affects 1-2% of the population in developed countries and ~50% of patients living with it are women. Compared to men, women are more likely to be older and suffer hypertension, valvular heart disease, and non-ischemic cardiomyopathy. Since the number of women included in prospective HF studies has been low, much information regarding HF in women has been inferred from clinical trials observations in men and data obtained from registries. Several relevant sex-related differences in HF patients have been described, including biological mechanisms, age, etiology, precipitating factors, comorbidities, left ventricular ejection fraction, treatment effects, and prognosis. Women have greater clinical severity of HF, with more symptoms and worse functional class. However, females with HF have better prognosis compared to males. This survival advantage is particularly impressive given that women are less likely to receive guideline-proven therapies for HF than men. The reasons for this better prognosis are unknown but prior pregnancies may play a role. In this review article we aim to describe sex-related differences in HF and how these differences might explain why women with HF can expect to survive longer than men.

Twenty-year survival following orthotopic heart transplantation in the United States

BACKGROUND

This study evaluated 20-year survival after adult orthotopic heart transplantation (OHT).

METHODS

The United Network of Organ Sharing Registry database was queried to study adult OHT recipients between 1987 and 1998 with over 20-year posttransplant follow-up. The primary and secondary outcomes were 20-year survival and cause of death after OHT, respectively. Multivariable logistic regression was used to identify significant independent predictors of long-term survival, and long-term survival was compared among cohorts stratified by number of predictors using Kaplan Meier survival analysis.

RESULTS

20,658 patients undergoing OHT were included, with a median follow-up of 9.0 (IQR, 3.2-15.4) years. Kaplan-Meier estimates of 10-, 15-, and 20-year survival were 50.2%, 30.1%, and 17.2%, respectively. Median survival was 10.1 (IQR, 3.9-16.9) years. Increasing recipient age (>65 years), increasing donor age (>40 years), increasing recipient body mass index (>30), black race, ischemic cardiomyopathy, and longer cold ischemic time (>4 h) were adversely associated with a 20-year survival. Of these 6 negative predictors, presence of 0 risk factors had the greatest 10-year (59.7%) and 20-year survival (26.2%), with decreasing survival with additional negative predictors. The most common cause of death in 20-year survivors was renal, liver, and/or multisystem organ failure whereas graft failure more greatly impacted earlier mortality.

CONCLUSIONS

This study identifies six negative preoperative predictors of 20-year survival with 20-year survival rates exceeding 25% in the absence of these factors. These data highlight the potential for very long-term survival after OHT in patients with end-stage heart failure and may be useful for patient selection and prognostication.

The Year in Cardiothoracic Transplantation Anesthesia: Selected Highlights from 2019

The highlights in cardiothoracic transplantation focus on the recent research pertaining to heart and lung transplantation, including expansion of the donor pool, the optimization of donors and recipients, the use of mechanical support, the perioperative and long-term outcomes in these patient populations, and the use of transthoracic echocardiography to diagnose rejection.

Ethical Issues in Decision-making Regarding the Elderly Affected by Coronavirus Disease 2019: An Expert Opinion

The coronavirus disease 2019 (COVID-19) pandemic is resulting in ethical decisions regarding resource allocation. Prioritisation reflects established practices that regulate the distribution of finite resources when demand exceeds supply. However, discrimination based on sex, race or age has no role in prioritisation unless clearly justified. The risk posed by COVID-19 is higher for elderly people than for younger people, so older adults should be prioritised in preventive measures. In the case of people who already have COVID-19, healthcare professionals might prioritise those most likely to survive. Making decisions based on chronological age alone is not justified; in addition to age, other aspects that determine theoretical life expectancy must be taken into account. Individualised correct prioritisation in the allocation of scarce resources is essential to good clinical practice.